Traveling wave tube amplifiers (TWTA), which are typically embodied as traveling wave tube modules, are predominantly used as power amplifiers in satellites. These modules comprise a traveling wave tube, which predominantly determines the high-frequency properties, and a power supply, which generates the supply voltages for the traveling wave tubes, a telemetry and/or telecommand interface to the satellite, and a controller. The traveling wave tube module can be supplemented by a preamplifier (also called a channel amplifier), which may also contain a linearizer. The preamplifier can be integrated with the other components in a housing. This combination is typically referred to as a high-frequency power module.
Traveling wave tube modules and amplifier modules in general can also comprise a protective function component, in which one or more protective functions are embodied, to protect the amplifier from damage, for example, from an excessively low supply voltage, an overload at the outputs of the power supply, an excessively high current on the delay structure, etc. If one of these protective functions is activated, the amplifier module automatically shuts down.
A ground station is typically informed via telemetry data, which are transmitted from the satellite to the ground station, about the shutdown or also about successful restarting of the amplifier module. However, it cannot be determined from the telemetry data why the device has displayed the malfunction or which protective function was active.
In general, telemetry data are provided to the satellite as an analog value in the case of analog data or as digital information in the case of status data or already digitized as a digital word from the amplifier module. A system of the satellite reads out the data at regular intervals, wherein the time between two read procedures is typically several seconds (for example, 60 seconds). If an automatic re-start of the amplifier module was successful, this is indicated by a corresponding status telemetry. However, it typically cannot be established from these data which parameter has triggered the protective function. The telemetry data are also not provided promptly as a result of the long read intervals.
For deep space missions, devices have been developed which, in the case of a malfunction, additionally indicate which parameter has triggered the protective function. However, if the device is completely shut down by the protective function, this information is lost. Furthermore, data of the telemetry are not provided promptly.